Subgrading machine



Feb. 25, 1947. K. MEISENBURG 4 SUBGRADING- MACHINE Filed March 17, 1944 6 Sheets-Sheet 1 mm mm Feb. 25, 1947. K. MEiSENBURG- SUBGRADING MACHINE 6 Sheets-Sheet 2 INVENTOR Kar/Me/se/wu/"g Filed March 17, 1944 MNN m. mm mm N M lclu- SUBGRADING MACHINE Feb. 25, 1947.

K. MEISENBURG SUBGRADING MACHINE e Sheets-Sheet! Filed March 17, 1944 9 0 a m 4 a 4 J J 4 w 6 4 E w 8 w .WUF .0 a. a m e MW m a j 3 u l v .55 \58 Kar/Me/lsenburg Feb. 25, 1947. v 2,416,401

v 'SUBGRADING MACHINE .Filed March 17, 1944 e Sheets-Sheet 5 I INVENTOR lr/Mezkenburg Patented Feb. 25, 1947 SUBGRADING MACHINE Karl Meisenburg, Pittsburgh, Pa., assignor to Blaw-Knox Company, Pittsburgh, Pa., a corporation of New Jersey Application March 17, 1944, Serial No. 526,992

1 This invention relates to a machine for pre-v paring a smooth earth surface, usually a subgrade upon which a hard pavement is to be laid.

Subgraders of several types are in common usein preparing the base for concrete roads. In using such machines, the procedure is to grade the earth upon which the pavement is to be laid, and to roll or otherwise compact it to an elevation a few inches higher than the desired final level, and then to out the surplus soil as accurately as practicable to the desired grade. Inpractice, the machines hitherto availablefor this work seldom leave the surface in a sumciently compact condition without re-rolling, and are, incapable of cutting into very hard soil. Attempts to overcome the latter defect hitherto have involved making the machines unduly heavy, introducing difilculties in respect to their supports and increasing the cost of the roadbuilding process as a whole.

' One object of this invention is to provide a machine able to trim the subgrade to a hard, smooth surface of the contour desired and to remove the trimmed soil laterally at or in advance of the cutting means, without permitting any loose earth to accumulate behind the latter, thus leaving the subgrade, after my machine passes thereover, in exactly the condition in whichit is left by the cutting means and not in that condition resulting from the scraping up of surplus material from above the cut surface. I

Another object of this invention is to operate the cutting means in a manner which will not impose shocks or jars of any magnitude upon the framework of the machine proper and thence onto the road rails or sub-soil upon which the machine is supported. The cutting means of the machine are mounted resiliently with respect to the. machine itself, and are advanced on the whole at the same speed as the machine, but the motion imparted to them to cause the cutting action is brought about by a series of rotating weights so mounted as to impart an oscillatory motion to the cutting means as they advance with the ma chine, along the roadway. This arrangement relieves the frame of the machine or the mechanism by which the machine is moved forward from the reaction of the impacts of the cutting means on the soil. My novel subgrader, herein described, is capable of finishing the subgrade to the desired degree of smoothness for pouring concrete without re-rolling, and is capable of cutting into Very hardand diflicultly penetrable soil. The inventionwill be explained in the course of the following. complete description referring to the accompany'ing drawings which illustrate a preferred em-* 13 Claims. (Cl 37108) bodiment and certain modifications. In the drawings,

Figure 1 is a plan view of the subgrader with certain parts omitted;

Figure 2 is a side elevation.

Figure 3 is a front elevation with certain parts omitted; s I

Figure 4 is a transverse section taken along the. line lV-IV of Figure 1;

Figure 5 is a partial longitudinal section taken along the plane of line V-V of Figure 1, with parts omitted;

Figure 6 is a horizontal section taken along the plane of line VI-VI of Figure 4 showing one form of soil-cutting member;

Figure 7 is a partial horizontal section taken along the plane of line VII-VII of Figure 3 with parts omitted;

Figure 8 is an enlarged vertical section taken along the plane of line VIII-VIII of Figure 6; I

Figure 9 is a horizontal section taken along the plane of line IXIX of Figure 8;

Figure 10 is a partial section similar to Figure 5 I showing a modification;

Car and drive mechanism The subgrader of my invention is embodied in a car I adapted to travel on road rails 2 (which constitute the side forms for the pavement slab of a road) or on a pavement slab or slabs on one or both sides thereof. The car has a frame coma posed of cross members 3, 4, 5 and 6 and spaced, central longitudinal members I. An operators platform (a is mounted onthe members I. To permit the adjustment of the machine for roads of different Widths, side frames or carriages 8 adapted to be adjusted laterally are mounted at the extreme outer sides of the machine and secured in adjustedposition by bolts or the like, not shown. dinal members 9 extending below the cross members 3 and 6. The rear ends of the side frames are slidable in guides Ill secured to cross meme her 5. At the forward end of each side frame, a

The side. frames include longitu 1 veyor to be described later.

3 depend from the side frames just inside the rails j 2. The main and" side frames are preferably-fabricated from structural shapes and plates as vided with a bearing box 23 thereon. trucks 24 are pivoted at 25 to arms 23. The arms 1 turbo shapes.

3 box 12 ,having sides 13, 13a, a top 14, an end wall l and a bottom I5, extends upwardly and inwardly between the cross members 3 and 4. The I I boxes are slidable between cross members 3 and 4 when the side frames are adjusted laterally,

and are adapted for cooperation with the con- Retaining plates l'l shown in the drawings. The remaining details of j i the construction thereof will be apparent without I The shafts H! are also provided with rubber-tired wheels 2 I adapted to 1 travel on the shoulder of an adjacent pavement slab; The adjustability of the side frames.per-

mits the machine to be set for roads of various widths.

At' th'e front end of the machine, eeeh side 1 frame has a housing ,22 extending inwardly beneath'the cross member 3'. The housing is prowheel are pivoted to the housing 22 at 27am have bearveniently be fabricated from plate and. strucand 2|. A hydraulic lift is pivoted to each arm 1 26? aajabent, its renters end and to the over-' hanging end 'or the. adjacent bearing box 23. Operation of the lift. thus causes the car In to betilte'd upward at the front end about therear 1 wheers. This permits the machine to be moved j along the rails without interference with the a ground, when itisnot engaged in cutting the sub- 1 grade.

Th /normal operating position of the frame which is illustrated in Figure 2, is deterthrough the box 23 and blocks 3i secured thereto.

The bolts are adapted to seat on the shoulders 3 23 of the arms 2-6. Nuts threaded on the bolts serve as stops to limit the downward tilting move- 1 merit of the car frame when engaged by the blocks 3|.

The car land the cutting member andiconveyor mounted thereon, to be described in detail later, are driven by any convenient source of power such as an internal-combustion engine '32. vThe A pinion 3-5 on the low- In each transmission, a qgm 39 is slidably of the point at which the subgrader is operating,

toprovide'thetraction necessary 'to advance the j machine. v heaves"najmbun'tea n the boxes 1:2. The 'two-' The cables pass over floating guide j further description. Stub shafts 19 are journaled' f in the side frames near the rear end thereof and 1 i are provided with flanged steel wheels?!) adapted to travel on the rails 2.

inglshoul'ders28 formedthereon. The housings, j 1 bearing boxes, wheel trucks and arms may c'oh- I e The trucks are" provided with Wheels 296, and Zia similar to the rear Wheels 20 3 mined by bearing bolts 30 extending downwardly mounted on the shaft 33 and is provided withv 1 pinionsof different sizes adapted alternately to j meshyvith gears secured to the drum of a winch 40. The winches are provided with cables 4! adapted to be secured to the road rails in advance 4 speed drive for the winches incorporated in the transmissions makes it possible to speed up or slow down one side of the machine relative to the other; as may be necessary to maintain the desired position of the car normal to the road rails, when rounding curves in the road.

Each transmission also includes a stub shaft 42 having a pinion 43 splinedethereonmeshing with gears 36a and 3% on shaftffilg, A "j'aw clutch 44 is mounted on the outer end of each shaft 42 and r the driven member thereof includes one sprocket of a chain-and-sprocket drive 45 for the shafts I9. When the clutches 44 are engaged the rear wheels are driven to move the machine backward. The shafts '42 are slidable in their bearings to move with the side-frames on adjustment thereof. The right-hand transmission also includes a lon- 'g'it'udinal shaft 46 extending through the cross member s5. This shaft is driven through bevel gearing 4'! by gear 35a which meshes with a gear 48 formed integral with th driving bevel gear.

The Sherrie dr'i'ves t eeenveyor to be described later. The shaft leana bevel gearing 41 may be provided in both transmissions, if desired.

Cutting members and actuating-mechanisms A plurality of subrremes' ts disposed side-by side and articulated together in groups are sus pendedr'f'rom the cross members 3 and 4. The subframes are fabricated from structural shapes as shown in Figure '7, and are arranged in two. groups, as shown inFigure' i each extending over half the width Of the machine. The suJofI'arhefs are suspended by meansof pins 50 and 51 carried by eyebolts 52 and '53 depending, respectively, fromthe cross members and a fabricated angle 542i, mounted on a plate 54 secured to the cross member 5. Thefpins 50 have a relatively loose fit in the subfr'a mes and thus provide an a1,-

ticulated relation between adjacent 'subfra'mes. The bolts 52 and 53 may. be adjusted vertically by means ofin'uts threaded thereon.

The bolts 52 and '53 when adjusted,.beingvery rigid and firmly anchored at. their. upper ends by means of their nuts, support the subframes 45in fixed position relative to; frame "I. Bolts 53 are further supported laterally by .a suitable fit in holes mpieteata. s

A group of separate oscillating. members 55 is suspended from the subframes 49 by flexible hanger bars 56 of spring steeladapted' to permit free oscillation of the members relative to their The bars '56 may be of supporting 'subframe. ci reular section with flattened ends, thetupper ends being secured between adjacent subframes as bymeans :of shimsan'cl'bolts, and the lower ends being secured'betweeneadjacen't cutting members in the same manner,

at the joints resulting from the vertical adjustment of bolts 5:2v for giving desired crown to the subgreue As shown in Figure 5, eachcutting member 55 is generally horizontal and comprises afplat'e having. its forward jportion bent downwardly and'fprovidedwith aihardened'toothed' cut ting edge 51. "stiffener bars '5'8 an'd 58a are welded edgewise tolthe lower; surface of the plate formiii'g the "cutting member. A thrust arm 59 depending from the subrmme 49. supports a olevis B'db'oltedi to the rear'edge of the cutting member; A spring '6'! between the ,clevis and, thrust arm resiliently tends to maintain the cutting member in. its mean. position between the limits of its oscillation as the car advances. The connection. qf'thelclevis to the cutting member and .t eitnrust There issufiicient 1oose-- ne'ss 'offiti'n these parts to permit the deflection,

arm is sufficiently loose tok'permit oscillation of the former in a horizontal plane. As shown in Figure 7, the bars 56 intermediate the subfram es on oneside of the central plane through the machine are'common to adjacent, members 55. If desired, each cutting member may independently be supported from thesubframe aboveby' a separate group of spring bars 56, one at each corner, there being provided for a group of three cutting members twelve such bars instead of eight as shown on the drawings. In'this case each cutting member may oscillate separately, although it is preferred that they all be synchronized'as to phase and frequency, whether the suspension of adjacent cutting members be'common or separate. Figure 6 is a plan view of an integral "cutting member 55a adapted to replace the three separate. cutting members 55 on one side of the machine as shown in Figure 1. The cutting member'55a adjustment of the latter to a generally curved eontour. Actuatingmechanism's 64 are mountedonthe' cutting members 55, as shown in Figure 4. In the case of the cutting member 5511, a plurality of actuating mechanisms are disposed thereon, as shown in Figure 6. The actuatingmechanisms are centrifugal oscillators. constructed as shown in Figures 8 and 9. Each oscillator-.64comprises. a housing 65 adapted to be set down into a hole of suitable shape formed in the horizontal portion of the cutting member, as clearly shown in Fig; ure 5. A shaft 66 is journaled in bearings 61 and has eccentric weights 68 keyed thereto. Other eccentric weights 69 are secured to a gear 10 journaled on the shaft 66 by bearings 11 A stub shaft 12 fixed in the housing 65 has a pinion I3 journaled thereon which meshes with a gear 14 keyed to the shaft 66. A shaft 15 journaled in the housing 65 on bearings 16 has a gear" 11 thereon meshing with the pinion 13. The shaft '15 also has a gear 18 thereon meshing with the gear 10. shaft 66 causes the weights 68 to rotate in one direction and the weights 69 to rotate in the other direction at the same speed. Byproperly detere mining the phase of the two sets of weights relative to each other, it is possible to impart transverse or longitudinal oscillations in a horizontal plane to the cutting member, or a combination of both. Covers 19 close the ends of the housing 65. An impeller 86 on the lower end of the shaft- I5 is provided for circulating lubricant contained within the housing 65. The im-peller delivers lubricant through a bore 8| in the shaft 66 to various levels in the vibrator by radial;- bores communicating therewith. Lubricant returns to the impeller through the lower bearings Gland a passage 82, or through ports 82a.

The shafts 66 of the several oscillators- 64 are driven by the engine 32. By means of a belt-drive. the engine operates a cross shaft v83 made up, of a plurality of sections connected by couplings and, extending through bevel gear units .84"'se-..: curedtov cross members 4 and5. uTelescoping By this construction rotation of the,

vertical shafts 84a. extend downwardly from' the units 84to theyibratorshafts and are providedwith universalcouplings adjacent both the bevel gear, units. andthe vibrators. It will be ap-: parent that in the arrangement shown the shaft 83 isdriven continuously but a suitable clutch may be provided to disconnect it from the engine when desired. Inany event, when the shaft 83 is driven,=,the eccentric weights of the oscillators arerotated to cause osciilationof the cutting members. The eccentric weights of all the oscillators, of course, will be positioned so that thecutting members vibrate in unison. A relatively small amplitude of oscillation, say inch, is suff cient and a frequency of about 2000 osci l lations per minute is satisfactory. It will be understood that when theweights 68 and 69 are at opposed positions, their centrifugal forces balance and there is no resulting force exerted on the cutting member. As the weights approach positions in which they are in overlying relation, an increasing horizontal force is applied to the cutting, member. A similar force in the opposite direction is applied when the weights have executed another half revolution.

The pointsat which the weights are in overlying relation may be disposed on a line parallel, to the edge of the cutting member or normal thereto merely by removing the pinion I3 and making the necessary'ad'justment of the phase relation of the two 'sets of weights. It is thus possible to cause the cutting member to oscillate i'n'thedirection of its cutting edge, giving'a' saw ing action or at right angles thereto resulting in a chiseling action. Either action is highly efle tive inaidingthe cutting member to penetrate thesoilbetween the road rails. It will'be obvious that suflicientclearance must be provided be-f 1 tween the latter and the outer cutting members to permit the desired oscillation, if it takes place in a direction parallel to the edge of the cutting;

member. a

Conveyor and pusher plate Spaced series of plates 85 and 86 extend trans versely of the car, each'plate of the two series. being secured to one of the subframes 49 and depending therefrom generally in vertical alinement with the cross members 3 and 4. Horizontal plates 81 secured to the latter provide bottom guide tracks for the upper run of a chain conveyor 88. The conveyor includes a pair of chains 89 having flights 90' in the form of flat platesv secured thereto at intervals and extending between the chains. As. shown more clearly in Figure 5, the conveyor flights 90 extend forwardly of the cutting edge of 51 as Well as above it. Top guide tracks 9| in the. form of narrow plates with upwardly curved ends are secured to the cross members 3 and ll to confine the upper run of the conveyor chains. The plates 85 and 83 have flanges 92 providing bottom guide tracks for the. Angle s 93' lower run of the conveyor chains. secured to the plates above the flanges confine the bottom run of the conveyor chains, The"v chains are trained over sprockets-M on a tailshaft 95. v The shaft 95 isjournaled in one of aseries of bearings 96 formed adjacent the ends f the cross members 3 and 4. The several mountings for the tailshaft thus afforded permit I mediate. the shaft. 95. 1 plates 85 and 86 are replaced when'the setting the chainsB'Sl' correspondinglychanged;

1 member.

1 98 adjacent the upper end thereof.

jacent their inner end. j ""Theb'ottom of the chute 98 is a continuation of'lithe bottom E5 of the box [2, The conveyor 1 8'8foperates in the manner of a drag-scraper con-. veyor to move soil across the cutting members 55 and.upwardly along the bottom I6 of the box 1 I2 and the bottom of the chute 98. i terminates a short distance below the extreme U 1 upper end of the chute and discharges soililo os- 1 ened by the cutting members into a pile In! at i one side of the right-of-way. Because of its l pivotal mounting at 99 the chute 98 may be swung 1 up to the position shown in dotted lines in Figure 3, after uncoupling the braces I00, to clear aerator The outer subframes' and of 'the'side frames is altered,and-thelength of I Asshownin-Figure 3, the conveyor guide tracks are adjusted by means of the eyebolts 52" and 53 to thesarne extent as the cutti-ng'members 55.

j Thusfthe' conveyor flights 90 are always the same distance above the forward edge of the cutting As shown in Figures 3 and 4, the sides I3 and bottoms I6 of boxes 12 formthe lower end of a chute cooperating with the conveyor 88. An ex'-.

adjustable bearings I02 mounted on the chute I d The shaft II is the head shaft of the conveyor, having f sprockets I 93. thereon around which the conveyor j chains are trained. The shaft IElI is driven by I shaft 46 through, a chain-and-sprocket drive I04. Chainid'ler sheaves I05 are mounted on a shaft 1 I2 adlllfi journaled in the sides I3i of the box The latter roadside obstructions or to facilitate traveling of themachine when not actually operating on the 1 subgrade;

It will'b'e observed that provision of duplicate 1 boxes. I2 at opposite sides of the machine permits i the discharge of soil to either side of the road I since the conveyor 98 may bemounted on the left-hand side of the machine as well as on'the right-hand side on which it is illustrated in Fig- I ure 3.

Pusher plates I08 are secured to the flanges At their lower edges,

members.

fine the loosened soil above the cutting members 1 so that it accumulates temporarily in the path of the'conveyor flights 90. 3 above described to sweep the accumulated soil 1 progressively across the width of the machine and The latter operate as into thechute 98. Each pusher plate extends :the width of a single subframe and thus does not interfere with the adjustment of the cutting 1 members and conveyor tracks toa curved contour; l

The outermost plates Hand 86 are pivoted at 91 to the sides of the boxes I2; -While 7 1 these pivot points at the sides of the machine are 1 fixed vertically, the intermediate portions of the conveyor tracks are adjustable for various contours along with the cutting members 55.

V Modifications I "Figure 10' illustrates certain parts onlyoff a modified form of subgrader. 'In this construetion a car frame includes cross members II'OI and Ill and longitudinal members II2 .I A cutting member II3 1s pivotally supported belOwjthe' frame on links II i andis provided with anoscil l'ator H57 shown ingreater detail in Figures 11' and. 12. The horizontal reaction on the cutting member resulting fromthe advance of the car is sustained by struts N6 of spring steel pivoted to the cutting member at Ill and support'edon plates. IIIB depending from the frame members I I2. The oscillator H5 is driven by a motor II 9 on the car frame through a chain-'and-sprocket drive I20 anda bevel-gear drive I2I', From the latter, a telescoping shaft I22 with universaljoints at each end extends to the oscillator II5'. While the motor. I I9 is shown as an electric motor; it will be evident that an internal-combustion engine maybe used Where convenience requires 7 driven thereby, the rotation of the eccentric: I weights .in opposite directions produces. a reci'p rocating force in the same manner as described in connection with. the oscillators 64. The oscil-j lator II5 when mounted as shown in Figure 10' causes reciprocation of the cutting member It;

in a horizontal plane in the direction parallel'fto' Reciprocation of the cutting its forward edge, member in the directio-nnormalto its forward edge would be produced if the oscillator were positionecl at right angles toits illustrated posi--' tion. A pusher plate I23 performs for the cutting member H3 the function of the pusher plate. I08 described above. a I It will be apparent from the foregoing'descripq tion and explanation that the subgrader of my invention has important advantages over subgraders known heretofore. In the first place, the machine of my invention finishes the subgrade to a sufficient degree of smoothness for pouring without re-rolling. This results principally from the fact that thecutting member oscillates at relatively'high frequency in ayhorizontal plane as it is being advanced in cutting through the The ability of the machine to finish the subgrade smoothly is further aided by the fact that the conveyor's weeps over thelength of the cutting member while the pusher plate prevents loosened soil from. passing tothe rear of the cutting member. The machine is positively driven by winches and cables and since there is thus no need for'extraweight, it need be made onlysuffi'ciently strong and heavy to withstand the forces to which it is subjected in use.

-The oscillations of the cutting member are transmittedto the car frame to a very limited extent only. The cutting member, being suspended on spring steel hangers, is relatively free" for movement and the spring cushions between. the cutting member and the thrust arms which absorb the reaction of the member, prevent vi--;

The oscillators ma .beeasily adjusted to cause vibration of the cutting flmemberparallel to its forward edge or normalthereto. The conveyor may be driven from either side of the machine and may be caused to discharge toward either side. Thevertically adjustability of the cutting members permits the subgrade to be finished to a curved contour as well as flat. The machine is relatively simple in constructionso that it can be manufactured andmaintained at moderate cost. p

- It is to be noted that-,-ginzorder to simplify the drawings, various control mechanisms have been omittedincluding gear-shifting and clutcheengaging levers and push-pull. rods connecting the levers to the elementst'o'j be actuated, as well as the hydraulic system for actuating the lifts 29.

Although I have illustrated and described but a preferred embodiment of the invention with certain modifications, it will be recognized that changes in the construction and arrangement of the parts may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim: a

*1. A s'ubgrading machine comprising a wheeled frame adapted to travel; on spaced supports, a horizontal cutting member suspended below said frame and extending across-the roadway between said supports adapted to cut a subgrade of prede termined depth and contour," means mounting said member on said frame for bodily oscillatory movement in a horizontal plane relative thereto, means for causing such movement of saidmemher, and a substantially vertical pusherplate se' cured to said frame in a' 'plane spaced rearwardly of the forward edge of the member, effective to prevent soil loosened thereby from flowing past saidmember.

2. A subgrading machine comprising a Wheeled frame adapted to travel on spaced supports, a

generally horizontal cutting member suspended below said frame and extending across the roadway between said supports adapted to cut a sub- .grade of predetermined depth and contour, means 7 mounting said member on said frame for bodily zontal cutting member suspended below said frame and directly supported by said subframes jointly, and means for vertically adjusting said subframes to vary the contour of said member.

4. A subgrading machine comprising a wheeled ;.:frame adapted to travel on spaced supports, a plurality of subframes suspended below said .xframe across the width thereof, a generally horizontal cutting member suspended below said frame and directly supported by said subframes 'jointly, means for vertically adjusting said sub- -frames to Vary the contour of said member, a conveyor traveling across said frame, and guides for the lower run of said conveyor mounted, on

- l0 saidfsubframes whereby they are adjusted to conform to said member. 7 f j 5. Asubgrading machine comprising a wheeled frameadapted to travel on spaced supports, a generally horizontal cutting member suspended below said frame and extending across the roadway between said supports adapted to cut a subgrade of predetermined depth and contour, flexible means mounting said member at. a predetermined elevation on said frame for bodily oscillat orymovementgin a horizontalplane relative thereto, said means being "adapted to limit the vibration transmitted to saidframe, an eccentric weight mounted on said member for rotation, means ontheframe for driving said weight to oscillate said member, and means including. vibration-absorbing means for positioningsaid member relative to the machine.

6. A subgrading machine comprising a wheeled frame adapted to travel on spaced supports,.a generally horizontal cutting member suspended below said frame and extending across the road way between said supports adaptedto cut a' subgrade of predetermined depthand contour, flexible means mounting saidrnember at a predetermmined elevation on said frame for bodily 059i}? latory movement in a horizontal plane relative thereto, said means being adapted to limit the vibration transmitted to saidframe, a plurality of systems of eccentric weightsspaced along said member and mounted for rotation thereon, common drive means on the frame for all said sys;

tems, and means including vibratiomabsorbing means for positioning said member jrelative 'to the machine. I "f '7; A subgrading machine con rrprisin'g awheeled frame adapted to travel on spaced supports; a generally horizontal" cutting member suspended below said frame and extending across the roadway between said supports adapted to out a subgrade of predetermined depth and contour, means way between saidsupports adapted to cut a 'subgrade of predetermined depth and contour, and means resiliently mounting said member on said frame for bodily movement in a horizontal plane relative thereto, including flexible hanger means for suspending the member and means including cushioning means tending to maintain, a mean position of the member relative to the frame in the direction oftravel, but permitting a cutting action of the member by reason of its deceleration on engaging the soil.

9. A subgrading machine comprising a wheeled frame adapted to travel on spaced supports, a generally horizontal cutting member suspended below said frame and extending across the roadway between said supports adapted to cut a subgrade of predetermined depth and contour, flexible hangers suspending the member from the frame and means yieldably tending to maintain a mean position of said member relative to said frame in the direction of ;travel but permitting member as a result of its retardation on engaging 1 the soil.

10, A ,sub rading machine comprising a 1 wheeled frame adapted to travel on spaced .supports, a enerally horizontal cuttin member suspended below said frame and extending across the as ee bodily movement relative thereto in ahoriaontal plane, thereby causing a cutting action of the its retardation on e aging .thcjsoil and yielsi- 5 5 able means tending to maintain said member in a m n position between the limits of its oscil- 1 lation' e 1.1, .A .subgi'ading machine comprising a ports, a generally vhorizontal cutting member suspe dedbelow said frame a d e tending across'the roadway between said supports adapted to cut a I Sub rade of predetermined depth and contour,

1 flexible hangers mounting said member on said 1 frame for bodily oscillatory movement transjversely of the frame, means for causing such movement of the member, whereby it exertsa sawing action on the soil, and cushioning means tending to maintain said member in amean posi- 1 tion in the direction of travel of the frame but permitting oscillation in that direction. f' comprising a wheeled frame adapted to travel on spaced sup- I ports, a generally horizontal cutting member sus- Number pended below said frame and extending across the roadway between said supports adapted to v12. A subgrading machine Y 20 j wheeled frame adapted to travel on spaced supi cuta'subgrade of predetermined depth and contour, .subframes below said frame havinghangers secured to said member, and means for vertically adjusting the several subframes to change said depth and contour. 13. A subgrading machine comprising a wheeled frame adapted to travel on spaced sup: ports, a horizontal cutting member suspended below said frame and extending across, the road+ way between said supports adapted to out a sub: 7

grade of predetermined depth and contourysub frames below said frame having means suspend ing said member at a fixed elevation, and independently adjustable :means supporting the subframes from the frame whereby 'the' shape -of the member maybe altered.

KARL MEiSENBURG. f r

CITED The following references are of record in {the file of this patent; V 1 UNITED SZRATESBA'IENTI'S Number Name Date 1,653,333 Baker c,., Dec. 20,-1927 2,200,724 Robins .a May 14, 1940 532,852 Wetmore l r Jan. '22, 1895v 1,140,985 Jones 'May 25, 1915 1,705,291 Horthy etal. Mar. 12, 1929 2,131,373 Foster ,a Sept. 2'7,- 1938 1,995,629 Baker -Mar. 26, 1935 2,072,150 7 Baker c.. .v-.. Mar. 2, 1937 1,841,799 Flynn Jan. 19, 1932 FOREIGN PATENTS Country Date 519,046 British ..Mar. 14, 194:0v 

